How Old Is My Dog? Identification of Rational Age Groupings in Pet Dogs Based Upon Normative Age-Linked Processes.

Naomi D Harvey

doi:10.3389/fvets.2021.643085

Abstract

Behavioral development is a lifelong process where cognitive traits such as learning and memory may be expected to take quadratic or linear trajectories. It is common practice for operational purposes to reduce study subjects into chronological categories when conducting research. However, there are no agreed-upon thresholds for this practice, and the lack of standardization may hinder comparison between studies of normative and pathological aging. In this perspective review, chronological categories have been identified that can be considered to represent normative cognitive and neurological aging in domestic family dogs. These categories work to capture age-related developmental trajectories for the majority of dog breeds. It is encouraged that researchers studying cognition and behavior, pathological cognitive deficits, or welfare of dogs across age categories utilize the categories presented here to best enable comparison between studies. The proposed groups could also support education programs informing owners of what behavioral changes to expect in their dog as they age, but they cannot be used to reflect health-based needs associated with breed-specific morbidity. The use of the age categories proposed here highlights significant welfare issues for breeds with the shortest average lifespans (e.g., the Great Dane). Studies show no evidence of an increased rate of behavioral or cognitive aging in short-lived breeds, and the shortest-lived breeds are most likely to die when classified by the proposed categories as Mature Adults. Adoption of these chronological categories in future research would aid comparison between studies and identification of non-normative age-related pathologies.

Highlights

Aging is a continuous, lifelong process that impacts health, behavior, and care requirements in humans and non-human animals
As raised in a comprehensive review of studies related to dog aging, there is a distinct lack of standardization in research when grouping dogs by age, which hinders cross-study comparisons [13]
This review aims to identify rational chronological categories for use in behavioral research, it must be noted that such categories are not recommended for use in predicting health needs because the thresholds would need adjusting for differing life expectancies between populations due to the reasons discussed earlier

Summary

Introduction

Lifelong process that impacts health, behavior, and care requirements in humans and non-human animals. The impact of aging on behavior is not straightforward (Figure 1), as age can have a linear relationship with certain behavioral traits [e.g., [6, 9]] but a quadratic relationship with others [e.g., [7, 10, 11]] or exhibit a steep change in later life [e.g., [6, 12]]. Because of the impact of age on behavior and health, age must always be considered in any study that includes dogs at differing stages of development. Age Groups in the Dog. In practical terms, most research studies tackle this by grouping dogs into chronological age categories (often treating them as linear variables). As raised in a comprehensive review of studies related to dog aging, there is a distinct lack of standardization in research when grouping dogs by age, which hinders cross-study comparisons [13]

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Conclusion